WeeChat has many new important features since some weeks:
- multi-windows management (with horizontal and vertical window split)
- buffers managed by number, with direct access by Alt+digit key or with new /buffer command
- auto jump to buffers with activity (Alt-A)

All new features are in CVS and development version. /window and /buffer commands are still under development.
Feel free to report any problem or suggestion to improve navigation between buffers/windows.